get selector from element

getSelector.js

/**
 * Is a selector returns only one result
 * @param {String} selector - number of threads to run
 * @return {Boolen} result
 */
const isUniqueSelector = (selector) => {
    const result = document.querySelectorAll(selector);
    if (result && result.length === 1)
        return true;
    return false;
};

/**
 * Get index of children element in its parent element
 * @param {Element} child - the child element
 * @return {Number} index
 */
const getChildIndex = (child) =>
    Array.prototype.indexOf.call(child.parentElement.children, child);

/**
 * Get selector from an element
 * @license BSD-3-Clause
 * @param {Element} element - the element to get selector
 * @return {String} the selector
 */
const getSelector = (element) => {
    if (!(element && element instanceof Element))
        throw new TypeError('getSelector: "element" is not an Element');
    if (element.id && isUniqueSelector('#' + element.id))
        return '#' + element.id;
    let selector = element.tagName.toLowerCase();
    if (element.className) {
        selector = '.' + element.className.replace(/ /g, '.');
        if (isUniqueSelector(selector))
            return selector;
        selector = element.tagName.toLowerCase() + selector;
        if (isUniqueSelector(selector))
            return selector;
    }
    if (element.parentElement) {
        const index = getChildIndex(element);
        if (index < 0)
            throw new Error('findChildIndex failed');
        return getSelector(element.parentElement) + '>' + selector + `:nth-child(${index + 1})`;
    }
};

export default getSelector;